- bic for a ball pen
- scotch for duct tape
- kalxon for a car honk
- rubalise for the white-and-red tape used in streets
- mobylette for that very specific old style scooter
- pédalo for the floating thingy on the beaches with pedals
As for cellophane I always called it "film plastique" or just "plastique", but this varies a lot from region to region and family to family.
As for Durit, it's actually a bit more interesting as the brand was genericised to "durite". It's so prevalent that we have expressions using it like "péter une durite" as a way to say "going crazy".
This floor is made of floor
Sure, it is also klaxon, cellophane and scotch.
Interesting, that champagne is the only case I know that won the fight. My friends often say sparkling wine for generic brands.
Frigidaire and its abbreviated form frigo is the standard name for a refrigerator (nobody ever says "réfrigérateur").
Kleenex is the standard word meaning "paper handkerchief".
Sopalin is the standard word for "roll of paper towels".
Many automotive parts are called from a brand name too : "Delco" is the only name an igniter is ever called; a flexible black tube is always called a "Durit" whatever its brand.
A modular pre-made, stackable non permanent housing module is an "Algeco".
A bus stop with a roof is called an Abribus.
A supermarket trolley is almost always called a Caddie.
A credit card is universally called a "Carte Bleue" or CB, to the point that people will happily use the nonsensical "CB" acronym for a credit card when speaking English.
Cellophane is called Cellophane. I don't even know of an another word for it :)